DNMT3L and leukemia: We examined two critical male gonocyte markers—5-methylcytosine (mC), a marker of DNA methylation, and promyelocytic leukemia zinc finger (PLZF) [47]—and found that most DNMT3L-positive germ cells exhibited strong 5-mC signals and some E-cadherin-positive cells had PLZF expression (Fig 6D and 6E), while no PLZF and 5-mC positive signals were detected in control ovaries (S5C Fig).